Recently, the prices of antiretroviral drugs have dropped dramatically, low cost generic drugs have become available, and further lowering of the price of patented drugs is anticipated thus paving the way for greater access to antiretroviral therapy for treatment of HIV disease in resource-constrained settings where the need is greatest. Hence there is a need to urgently develop innovative strategies to provide antiretroviral therapy safely, effectively and with high levels of adherence in the context of under- developed health care delivery systems. This CAPRISA project proposes the strategy of linking antiretroviral therapy to the widely available, affordable and sustainable tuberculosis directly observed therapy strategy. It proposes that such a strategy, by addressing issues of therapeutic potency and adherence, will enhance therapeutic outcome for both diseases. A once a day regimen of didanosine (ddl), lamivudine (3TC) and efavirenz will be used in combination with conventional anti-tuberculosis therapy. Since tuberculosis is the commonest presenting illness in AIDS patients in much of the developing world, the integration of HIV and tuberculosis care is an efficient method of identifying those in greatest need of antiretroviral therapy. Eligible patients, who are co-infected with HIV and tuberculosis, will be randomized to either the intervention arm, where both antituberculosis and antiretroviral drugs are provided through directly observed therapy with an enhanced adherence intervention, or the control arm where they receive anti-tuberculosis treatment through the existing directly observed therapy program. Upon completion of tuberculosis therapy at 6 months, the patients in both study arms are provided ongoing HIV care, which includes self-administered anti-retroviral therapy, at an AIDS clinic at a local hospital. The primary endpoint is the case fatality rate at 18 months after the diagnosis of the tuberculosis-HIV co-infection. The secondary outcomes include the impact of the intervention on the patient's clinical status, viral load, CD4 count, drug adherence, drug resistance, tuberculosis cure rates, tuberculosis relapse rates and drug adverse events. The findings of this study could have a major impact in resource-constrained settings with existing tuberculosis directly observed therapy programs, as it would provide an affordable and effective strategy for the successful implementation of antiretroviral therapy.